1. Field of the Invention
The present invention relates to an image processing device, its program product and method. In particular, the invention relates particularly to an image processing device, its program product and method for synthesizing foreground image data consisting of character or graphic images with background image data.
2. Description of the Related Art
The presentation materials that are printed on overhead projector sheets often contain foreground image data containing character images, etc., placed in front of background image data.
However, there are cases where the boundaries of the foreground image data and the background image data become unidentifiable depending on the colors of the background image data that exist in the areas surrounding the foreground image data such as character images, etc. and consequently, the character images, etc. stop being conspicuous completely.
As a means to solve such a problem, a technology has been known in which the colors of the foreground image data such as character images are changed depending on the colors of the background image data in order to make the foreground image data such as character images stand out among the background image data.
For example, Publication of Unexamined Japanese Patent Application, JP-A-10-293835 discloses a technology of adjusting colors of character images as character images appear differently depending on background image data when character images and their background image data are synthesized. Publication of Unexamined Japanese Patent Application, JP-A-7-256972 discloses a technology, for a case when character images are synthesized with another images and the density difference between the both images is within a certain preset value, of changing the density of at least one of the both images in the areas where the both images overlap each other.
However, in those technologies mentioned above, since the color adjustment is done independently to each area or pixel of character images, there can be a case where character images, which appear as the same color on the original document, are adjusted to different colors depending on the colors of the background image data.
Therefore, it has been a problem that, when character images obtained by reading an original document on which characters are color-coded depending on the function of each character, such as a part of title, subtitle, and keyword, are synthesized with the background image data, color-adjusted character images after synthesization lose the color-coding information completely.